Please do remember that the type of "therapy" most hotline volunteers give out is Rogerian by nature. This is "humanism."

"Humanism is permeated (1) by such concepts as external validity, meaning,
understanding, subjectivity, relevance, and value, and (2) by such goals or phenomena
as authenticity, self-actualisation, creativity, development of meaningful human
relationships, knowledge of innermost feelings, expanding one’s awareness, and love.
In a sense, humanism represents (1) a return to common-sense psychology, in which a
person’s goals, feeling, desires, and the like are a primary concern; and (2) a revival
of interest in such Christian values as love, concern, goodness. "

It doesn't give much support to someone suffering with PTSD. Cognitive Behavior Therapy is good for learning to live with PTSD, by changing you outlook etc. CBT is a therapeutic approach that addresses the thoughts that reinforce negative belief systems, and the behavior that occurs as a response to those beliefs. Flashbacks are responses to things the brain/mind believe are happening now.